Protocols supporting network access by mobile devices are well known. For example, Mobile-IP is an extension to the internet protocol (IP) that allows mobile nodes to receive datagrams wherever they happen to be attached to the Internet. To support the mobility of network nodes, Mobile-IP describes the additional control messages that are needed to allow the mobile nodes to manage their IP routing tables. The Mobile-IP protocol is described in C. Perkins, Ed., “IP Mobility Support for IPv4,” RFC 3344, August 2002, published by the Internet Society of Reston, Va., and incorporated herein by reference in its entirety. Mobile-IP supports the movement of IP hosts between different sub-networks without the need to tear down established transport layer sessions. Other documents relevant to Mobile-IP include H. Chaskar, Ed., “Requirements of a Quality of Service (QoS) Solution for Mobile IP,” RFC 3583, September 2003; P. Calhoun et al., “Diameter Base Protocol,” RFC 3588, September 2003; D. Cong et al., Eds., “The Definitions of Managed Objects for IP Mobility Support using SMIv2,” RFC 2006, October 1996; and G. Montenegro, Ed., “Reverse Tunneling for Mobile IP, revised,” RFC 3024, January 2001, all published by the Internet Society of Reston, Va., and all of which are incorporated herein by reference in their entireties.
Protocols such as Mobile-IP are designed to provide appropriate routing for packets as a mobile device changes its network attachment point. Those skilled in the art will be aware that different service providers will provide different service levels, requiring different quality of service (QoS) treatment for traffic originating from, or destined to be received by, a mobile device. Such QoS requirements are further discussed in H. Chaskar, Ed., “Requirements of a Quality of Service (QoS) Solution for Mobile IP,” RFC 3583, September 2003, published by the Internet Society of Reston, Va., and incorporated herein by reference in its entirety. Accordingly, parties contracting for various service levels may desire a regular service report that provides information regarding an observed service level over a specific period of time. However, although mechanisms for supporting mobile devices are known, ways are presently lacking for providing a performance monitoring report reflecting an audit of the service level experienced by the mobile device.
Conventional systems for monitoring and evaluating network performance present severe deficiencies when applied to networks that support mobile devices. For example, a traditional internet protocol (IP) network performance evaluation system is usually composed of two elements, a source and a sink. The source sends time-stamped traffic, while the sink intercepts packets generated by the source. After inspecting and analyzing packets by the sink, a conventional system will then provide the results for a testing session. Such systems are capable of evaluating end-to-end performance, i.e., performance from one fixed point attached to a network to another fixed point attached to a network, but are not designed to accommodate systems supporting mobility.
In a network including mobile devices, conventional network monitoring and evaluation systems treat the path from the source to the sink as one entity. However, in a network supporting mobile devices, this path may actually span multiple network service providers, and multiple network technologies, each potentially providing a different service level. If measurements over multiple segments of a network (including a network comprised of several service providers' networks) are needed, then multiple instances of source-sink pairs are needed at different points of the network. However, such a configuration is characterized by considerable overhead and costs that generally limit implementation of conventional network monitoring and evaluation systems. The limitations of conventional network monitoring and evaluation systems are particularly disadvantageous for mobile environments, in which a mobile device can readily and dynamically move to any service area out of many.
Further, conventional network monitoring and evaluation systems disadvantageously lack visibility into the mobility support protocol, preventing such systems from correlating network behavior to the mobility protocol events. This lack of visibility impedes the ability of conventional network monitoring and evaluation systems to differentiate results reported from a wired network from those reported from a wireless network. This is a critical shortcoming because wired and wireless networks will most likely be evaluated according to different QoS metrics based on corresponding differences in the physical characteristics of wired and wireless networks.
Moreover, conventional network monitoring and evaluation systems are not able to differentiate service degradation events caused by network failures from degradations caused by mobility related events. That is, a mobile device may suffer diminished service as it moves around, or may lose service altogether when it falls out of the range of any network attachment point. However, for conventional network monitoring and evaluation systems, such an event is indistinguishable from, e.g., a hardware failure at some point within the network.